It has long been known that certain bis-biguanide compounds can be used in oral germicidal compositions: U.K. Pat. Specification No. 1,365,030 of Merck & Co., Inc. published on Aug. 29, 1974. As such, these compounds cause some inhibition of the formation of dental plaque. However, such compounds do not completely inhibit the formation of dental plaque; there is substantial opportunity for improving such efficacy of these compounds.
It is also well known that certain bis-biguanide compounds, when used as anti-plaque agents, cause unslightly staining of teeth. Many procedures have been proposed to reduce such tooth staining: U.S. Pat. Nos. 3,925,543 issued to Donohue on Dec. 9, 1975; 3,934,002 issued to Haefele on Jan. 20, 1976; 3,937,805 issued to Harrison on Feb. 10, 1976; 3,937,807 issued to Haefele on Feb. 10, 1976; 3,957,967 issued to L'Orange on May 18, 1976; 4,051,234 issued to Gieske and Juneja on Sept. 27, 1977; 4,080,441 issued to Gaffar, deVries and Carroll on Mar. 21, 1978; 4,118,474 issued to Gaffar and Niles on Oct. 3, 1978; 4,183,916 issued to Rhodon on Jan. 15, 1980 (and corresponding Re. 31,397 reissued on Sept. 27, 1983); 4,256,731 issued to Curtis and Bhargava on Mar. 17, 1981; and 4,273,759 issued to Gaffar and Gaffar on June 16, 1981.
Although the above methods may reduce the tooth stain caused by the bis-biguanide compounds, better methods for further reducing such stain are highly desirable.
Peroxy compounds, including monoperoxyphthalic compounds, have been used for preventing or removing stains from teeth or dentures: U. S. Pat. Nos. 3,988,433 issued to Benedict on Oct. 26, 1976; 4,273,759 issued to Gaffar and Gaffar on June 16, 1981; 4,490,269 issued to Gallopo on Dec. 25, 1984; and European Pat. Application No. 0,133,354 of Interox Chemicals, Ltd., published Feb. 20, 1985. Monoperoxyphthalic acid compounds have also been disclosed in anti-gingivitis compositions: U.S. Pat. Nos. 4,670,252 issued to Sampathkumar on June 2, 1987; and 4,716,035 issued Sampathkumar on Dec. 29, 1987.
It is an object of the present invention to provide a method for reducing or inhibiting the formation of plaque on dental surfaces by treating such dental surfaces, in part, with a bis-biguanide compound.
It is a further object of the present invention to provide an enhanced reduction in plaque compared to that normally achieved by treatment with such a bis-biguanide compound.
It is a still further object of the present invention to achieve such enhanced reduction of plaque with substantially less staining of teeth than normally occurs during treatment with such a bis-biguanide compound.